Galangal (Alpinia galanga (Linn.) Willd) is a perennial aromatic rhizomatous plant with great industrial importance. In this study, four major antibacterial compounds were isolated from galangal and further identified as hydroxycinnamaldehyde, cinnamaldehyde, coumaryl alcohol, and 1′-acetoxychavicol acetate (ACA). Among them, ACA was a less investigated antibacterial compound in galangal, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) 0.313 and 0.625 mg/mL, respectively, against multidrug-resistant Staphylococcus aureus SJTUF 20758. The mechanism study found that ACA significantly influenced the bacterial morphology and damaged the bacterial cell membrane integrity. Furthermore, quantitative proteomic analysis indicated that ACA at sub-MIC, on one hand, inhibited the expression of proteins associated with cell wall and membrane synthesis, osmotic regulation, and bacterial adhesion and invasion. On the other hand, it increased the expression of proteins pertinent to oxidative stress response, respiratory chain, and ATP synthesis. Therefore, ACA might initially target cell membrane by changing the expression of key membrane proteins involved in maintaining normal cell membrane functions, leading to the damage of cell membrane integrity, and also might trigger the survival response of bacteria. In general, to the best of our knowledge, it is for the first time to clarify the antibacterial mechanism of ACA. In addition, galangal is a promising spice rich in antibacterial compounds, especially ACA, which may be used as natural preservatives in the food industry.

高良姜 ( Alpinia galanga (Linn.) Willd) 是一种多年生芳香根茎植物，具有重要的工业意义。在这项研究中，从高良姜中分离出四种主要的抗菌化合物，并进一步鉴定为羟基肉桂醛、肉桂醛、香豆醇和 1'-乙酰氧基茶酚乙酸酯 (ACA)。其中，ACA是一种在高良姜中研究较少的抗菌化合物，对耐多药金黄色葡萄球菌的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）分别为0.313和0.625 mg/mLSJTUF 20758。机制研究发现，ACA显着影响细菌形态，破坏细菌细胞膜完整性。此外，定量蛋白质组学分析表明，一方面，亚 MIC 的 ACA 抑制与细胞壁和膜合成、渗透调节以及细菌粘附和侵袭相关的蛋白质的表达。另一方面，它增加了与氧化应激反应、呼吸链和 ATP 合成相关的蛋白质的表达。因此，ACA可能通过改变参与维持正常细胞膜功能的关键膜蛋白的表达来初步靶向细胞膜，导致细胞膜完整性受损，也可能引发细菌的生存反应。一般来说，据我们所知，首次阐明ACA的抗菌机制。此外，高良姜是一种很有前途的香料，富含抗菌化合物，尤其是 ACA，可在食品工业中用作天然防腐剂。